Arterial blood pressure in adolescents during exercise stress testing

Abstracts

OBJETIVO: Descrever a resposta da pressão arterial em adolescentes submetidos ao teste de esforço. MÉTODOS: Foi realizado estudo transversal de 218 adolescentes entre 10 e 19 anos (131 do sexo masculino) submetidos a teste ergométrico, e descrita a freqüência cardíaca máxima, tempo de exercício, consumo máximo de oxigênio, pressão arterial sistólica (PAS) e diastólica (PAD) de repouso, no esforço máximo e aos seis minutos da recuperação. RESULTADOS: No repouso, a PAS teve valores maiores no sexo masculino e a PAD não mostrou diferença entre os sexos, porém ambas aumentaram com a idade. No exercício ocorreu elevação da PAS e queda da PAD em ambos os sexos. A variação da PAS foi maior no sexo masculino, principalmente acima dos 14 anos. CONCLUSÃO: A análise dos resultados demonstrou que a PAS durante o exercício teve relação direta com idade, peso, altura e índice de massa corpórea do indivíduo e a PAD teve relação apenas com a idade.

Pressão arterial; teste de esforço; saúde do adolescente

ORIGINAL ARTICLE

Arterial blood pressure in adolescents during exercise stress testing

Mônica de Moraes Chaves Becker; Odwaldo Barbosa e Silva; Isaura Elaine Gonçalves Moreira; Edgar Guimarães Victor

Universidade Federal de Pernambuco - Recife, PE - Brazil

^{Mailing Address}

SUMMARY

OBJECTIVE: Describe arterial blood pressure response in adolescents undergoing exercise stress testing.

METHODS: This was a cross-sectional study conducted with 218 adolescents (131 of whom were males), aged between 10 to 19 years, undergoing exercise stress testing. Maximum heart rate, total exercise time, maximum oxygen uptake, systolic blood pressure (SBP) and diastolic (DBP) at rest, during maximal physical exertion and at six minutes of recovery were measured.

RESULTS: At rest, SBP values were greater in males and no difference was found in DBP between genders, although both increased with age. During exercise, SBP rose and DBP fell in both genders. SBP variation was greater in men, particularly in those over 14 years of age.

CONCLUSION: Analysis of results showed that during physical exercise, SBP had a direct relationship with the individual’s age, weight, height and body mass index, whereas DBP bore a relationship to age only.

Key words: Exercise stress test, adolescents, arterial blood pressure.

Introduction

Arterial blood pressure (BP) is the main element used to indirectly assess the heart’s inotropic response to physical exertion associated with the level of exercise tolerance.¹ To date, there is no consensus over the normal values of blood pressure variation with physical exertion. Further studies should be conducted to establish patterns for young and old, male and female, white and black individuals.¹ The hyperreactive response of BP to physical exertion in normotensive individuals has a predictive value for the later development of arterial hypertension, with a 2-4 fold increased probability of developing this clinical condition^1-3.

The exercise stress test (EST) in children and adolescents has several indications, among which the assessment of the levels of functional capacity to participate in vocational, leisure and sport activities, as well as to observe the arterial pressure response to exertion^4,5.

Several studies have shown hemodynamic responses and gas exchanges in adults who do the exercise stress test with a ramp protocol^6-10. Most studies with children and adolescents are performed on a treadmill according to the Bruce protocol^5,11,12, but many do not report data on the arterial blood pressure response.

This study was undertaken to: 1) describe arterial blood pressure response in adolescents undergoing the treadmill exercise test; 2) describe systolic and diastolic arterial pressure values at maximal physical exertion and at six minutes after the exercise; 3) describe systolic and diastolic pressure variations during exertion; 4) determine the role of gender, age, weight, height and body mass index (BMI) on the behavior of arterial pressure during physical exertion.

Methods

A descriptive case series-type study was carried out with data from the ergometric tests conducted by one single investigator from April 1998 to April 2004. One hundred and thirty-one male and 87 female adolescents with no known cardiac disease were selected. They were 10 to 19 years old (mean age 13.7+ 2.5 years) and were referred for exercise stress tests to primarily assess functional capacity, arrhythmia or chest pain. Tests from healthy individuals with a HR greater than or equal to 180 bpm who interrupted the test because of fatigue were included. Patients with systemic blood pressure referred for BP evaluation or who were on medications that could interfere with the behavior of arterial pressure (bronchodilator, beta-blockers and sympathomimetic agents) were not included.

Guidelines set by the Brazilian Society of Cardiology were followed as to the temperature and humidity in the laboratory. Body weight and height measurements were obtained using a Filizola anthropometric scale, and participants were classified as to the presence of obesity according to the criteria described by Cole et al¹³. Before placing the electrodes for electrocardiographic monitoring, each placement site was cleaned with an alcohol swab. Before the test, anamneses were obtained and all patients underwent physical examinations, heart rate and arterial blood pressure measurements, as well as a surface electrocardiogram; these procedures were repeated every two minutes during the test. After the stress test, patients were monitored during six minutes or more when necessary. Arterial blood pressure was measured with an aneroid sphygmomanometer that is calibrated twice a year. The tensiometer cuff width measured approximately 2/3 of an arm length and was appropriately fit according to the subject’s size.

All participants did the treadmill exercise test using a ramp protocol, with small continuous increments in exercise intensity and speed, and treadmill inclination adjusted according to the patient’s age and gender¹⁴. Korotkoff phase I was used to define systolic BP (SBP) and phase V was used for the diastolic BP (DBP)^15-18. For the analysis of the results, measurements of BP at rest, at maximal exertion and six minutes after the test were used.

Participants were assigned to 5 groups according to their age: 10 to 11 years; 12 to 13; 14 to 15; 16 to 17, and 18 to 19 years. The comparison among the age groups and genders was made using the variance analysis (ANOVA) and the non-paired Student’s t-test, respectively. The linear correlation among the variables was also analyzed. When needed, the Mann-Whitney test and the paired Student’s t-test were used. Error was considered as a=5% (significance p<0.05). Data were processed using Microsoft^(R) Excel 8.0, whereas the statistical analysis was performed using Sigmastat 3.0 and SPSS (Statistical Package for Social Science), version 8.0.

The project was presented and approved by the Human Research Ethics Committee of the Centro de Ciências da Saúde of the Universidade Federal de Pernambuco.

Results

In the study population, 79.8% had a normal BMI according to the criteria described by Cole et al¹³.

The duration of exercise was 10:57±01:35 min. for males and 10:05±00:35 min. for females (p<0.001). No significant difference was found by comparing the age groups of patients of the same gender. The maximal heart rate was similar in both genders (192±08 bpm). Among male patients, maximum HR values were smaller in the group 10 to 12 years of age (p = 0.021). Maximal inclination and velocity and VO₂ max. were greater among boys (16.9±2.9%, 8.8±1.1 km/h and 55.7±7.4 ml/kg/min, respectively) than among girls (15.6±2.1%, 7.6±0.8 km/h and 46.7±5.8 ml/kg/min, respectively), with p<0.001. No significant difference was identified in the analysis by age groups.

Arterial pressure behavior - Resting DAP showed no significant difference between genders (p=0.578). Resting SAP was greater in males when compared to females (p<0.001). A similar resting BP pattern was observed in all periods evaluated during the stress test, that is, with no difference in DBP between genders and a greater SBP values for boys (Tabs. 1 and 2).

A positive correlation was observed between the resting systolic and diastolic BP and age, weight, height and BMI (except for systolic BP and BMI in girls).

The relationship between the maximum SBP measured and the independent variables in the analysis shows positive and statistically significant correlations for both genders. The correlation between the maximum DBP measured and age, height, weight and BMI shows a significant association with age in both genders. Among girls, a significant correlation between the maximum DBP and weight and height was also observed.

For all age groups and both genders a rise in SBP and a drop in DBP values were observed during exercise. The SBP variation (DSBP) was 20.3±13.9 for females and 30.1±17.3 for males (p<0.001). The DBP variation (DDBP) was negative 11.4±10.1 for females and 13.9±14.2 for males (p=0.324). The greatest variations in SBP were observed in the older aged groups (over 14 years) for both genders, particularly among boys.

A significant and positive association was found in all correlations for the DSBP variable and all independent variables analyzed for both genders. The same thing happened for the DSBP/MET variable.

Using the analysis of variance (ANOVA) and according to the classification of obesity¹³, a difference was observed in maximum SBP, DSBP, and SBP in the first minute of recovery (p=0.022, p=0.032, and p=0.010, respectively) among overweight and obese adolescents and those with a normal BMI.

Among boys, the SBP measured in the sixth minute after exercise (115.5±13.1 mmHg) was similar to the resting SBP (114.6±11.3 mmHg). Among girls, the measurement of SBP in the sixth minute after exercise (107.1+8.7 mmHg) was lower than the resting SBP (109.3+9.9 mmHg), with a significant difference (p=0.028). The DBP in the sixth minute after exercise (males 63.4±10.0 mmHg and females 62.7±8.4 mmHg) was smaller than the resting DBP (males 70.2+7.5 mmHg and females 69.6±7.4 mmHg), with a significant difference (p<0.001) in both genders.

Discussion

The importance of knowing the arterial pressure response to exercise in children and adolescents has been the focus of several studies in many countries, and these have confirmed that there are differences when diverse populations are compared^5,12,19-23. Some of these differences can be attributed also to the different methodologies and test protocols used. In most studies, children and adolescents were evaluated by means of multistage protocols, particularly the treadmill test developed by Bruce.

In this series, no difference was observed in resting DBP between the two genders. Increasingly greater values were observed with age, mainly from 16 years on, in both genders. Resting SBP values were significantly greater among males (p<0.001). As for females, no difference was found among the age groups. Mafulli et al¹² and Ahmad et al²² reported similar findings on the behavior of SBP at rest. However, other authors^19,20 did not identify differences between genders.

Resting SBP values described for a North-American population are slightly lower than those in this study²². This may be due to the different age groups evaluated in both studies. The DBP values at rest are also different. The use of different criteria to define DBP in both studies may explain this dissimilarity since the North-American population study had defined the Korotkoff phase IV as the criterion for DBP determination.

As to the behavior of BP during physical exertion, SBP levels for children and adolescents at maximal exhaustion are expected not to exceed 200 mmHg. A significant increase in DBP during physical exertion is uncommon, and usually the values at rest either drop or remain unchanged⁴.

Studies conducted with children and adolescents using the Bruce protocol have consistently reported a SAP behavior similar to that observed in adults, i.e., a rise in tension levels with exercise^{5,12,19,20,22}. However, these same studies are controversial as to DBP behavior. Some have shown a drop in DBP, whereas others have reported the maintenance of the levels observed at rest, and seldom, a rise in diastolic tension levels.

The findings in this study were similar to those reported in medical literature, i.e., a rise in SBP and a drop in DBP levels during physical exercise for both genders in all age groups. As expected, the magnitude of the SBP increase was greater among male patients since after puberty men have greater maximal systolic volumes than women. Increases in age, height, and weight resulted in increased SBP levels in both genders, more clearly among males.

Similarly to the findings reported by Ahmad et al²², the greatest variations in SBP were observed in the age groups over 14 years for both genders. However, variations of SBP, as well as those of the maximal exertion SBP reported by these authors, are greater than those identified in this series.

Studies conducted with children and adolescents using the Bruce protocol ^5,12,19,22 showed higher SBP levels than those observed in this study, even for those who used a similar BP measurement method. The greater BP levels were reported in studies that used an automatic measurement method^19,22. Although maximal exertion BP could not be measured in many patients of this series, even when only adolescents with clearly auscultated BP were considered, the difference relative to the studies on the Bruce protocol remains. This may reflect a better adaptation of the body to the ramp protocol in which the workload is increased slowly and frequently, with no abrupt changes, so that the arterial blood pressure also rises more gradually.

The exertional DBP variation was also greater among males, but it shows a drop with exercise in both genders and for all age groups evaluated. A significant association was observed only for age related to the maximum DBP measured, with levels in subjects over 14 years of age among females and over 16 years of age among males. This DBP behavior during exercise is different from that of other studies^12,19,20,23 that reported unchanged DBP levels during exercise or a tendency to decrease. In the study conducted with the North-American population²², contrary to the findings in medical literature and in this series, a rise in DBP with exercise was reported.

In one study undertaken in Venezuela²⁴ with children and adolescents from 8 to 17 years of age using the Cumming protocol, a SBP variation of up to 30 mmHg was found to be a normal response to exercise. In this series, a similar variation in SBP was observed, though with a significant standard deviation (DSBP: 30.1+17.3 mmHg). This may be due to the different age groups evaluated in the studies. The assessment of adolescents at an age group closer to the transition to adulthood, when the DSBP is expected to be over 35 mmHg, may have also played a role.

In this study, overweight or obese adolescents had higher arterial blood pressures at maximal exertion and DSAPs when compared to those with normal BMIs (p=0.002 and p=0.0032 respectively). This shows the influence of hyperinsulinemia, likely to affect overweight and obese patients, on the cardiovascular system and on the response to exercise.

As to the BP behavior after the exercise, Arenas et al²³ have shown the return of BP to baseline levels after approximately nine minutes of recovery. Ahmad et al²² observed a similar pattern, with the BP reaching levels similar to those at rest ten minutes after the exercise. In this series, a gradual decrease in systolic and diastolic components of the arterial pressure was observed, reaching levels similar to those at rest in the sixth minute.

The BP findings described may serve as a comparison to other studies that use the ramp protocol to evaluate adolescents (Tabs. 1 and 2). This series, that described the behavior of arterial pressure on exertion among 218 otherwise normal adolescents, is part of a more comprehensive project involving a second group with suspected arterial hypertension and a third study underway which is evaluating overweight or obese adolescents and a normal-weight control group.

The results obtained in this series allow us to conclude that the behavior of arterial blood pressure under physical exertion in healthy adolescents shows a rise in the systolic component and a drop in the diastolic component in both genders. Arterial blood pressure during physical exertion has a direct relationship with age, weight, height, and BMI in both genders, whereas the diastolic arterial pressure has a direct relationship with the individual’s age in both genders.

Potential Conflict of Interest

No potential conflict of interest relevant to this article was reported.

References

Manuscript received May 2, 2006; revised manuscript received August 31, 2006; accepted October 9, 2006.

• 1. II Diretrizes da Sociedade Brasileira de Cardiologia sobre teste ergométrico. Arq Bras Cardiol. 2002; 78 (Suppl 2): 1-14.
• 2. Murad Neto A, Bortolotto LA. Teste ergométrico e hipertensão arterial. Rev Soc Cardiol Estado de São Paulo. 2001; 11: 610-8.
• 3. Singh JP, Larson MG, Manolio TA, ODonnell CJ, Lauer M, Evans JC, et al. Blood pressure response during treadmill testing as a risk factor for new-onset hypertension. Circulation. 1999; 99: 1831-6.
• 4. Washington RL, Bricker T, Alpert BS, Daniels SR, Deckelbaum RJ, Fisher EA. Guidelines for Exercise Testing in the Pediatric Age Group. From the Committee on Aterosclerosis and Hypertension in Children, Council on Cardiovascular Disease in the Young, the American Heart Association. Circulation. 1994; 90: 2166-79.
• 5. Bozza A, Loos L. O teste de esforço em crianças e adolescentes. Experiência com brasileiros normais. Rev SOCERJ. 1995; 7: 19-25.
• 6. Vivacqua R. Considerações sobre o protocolo em rampa aplicado no teste ergométrico. Boletim do Departamento de Ergometria e Reabilitação Cardiovascular / SBC. 1999; 18: 16-7.
• 7. Whipp BJ, Davis JA, Torres F, Wasserman K. A test to determine parameters of aerobic function during exercise. J Appl Physiol. 1981; 50: 217-21.
• 8. Matthys D, Pannier JL, Taeymans Y, Verhaaren H. Cardiorespiratory variables during a continuous ramp exercise protocol in normal young adults. Acta Cardiol. 1996; 51 (5): 451-9.
• 9. Myers J, Buchanan BSN, Smith D, Neutel J, Bowes E, Walsh D, et al. Individualized ramp treadmill: observation on a new protocol. Chest. 1992; 101: 2363-41S.
• 10. Will PM, Walter JD. Exercise testing: improving performance with a ramped Bruce protocol. Am Heart J. 1999; 138 (Pt 1): 1033-7.
• 11. Cumming GR, Everatt D, Hastman L. Bruce treadmill test in children: normal values in a clinic population. Am J Cardiol. 1978; 41: 69-75.
• 12. Maffulli N, Greco R, Greco L, DAlterio D. Treadmill exercise test in Neopolitan children and adolescents. Acta Paediatr. 1994; 83: 106-12.
• 13. Cole TJ, Bellizzi MC, Flegal KM, Dietz WH. Establishing a standard definition for child overweight and obesity wordwide: international survey. BMJ. 2000; 320: 1-6.
• 14. Barbosa e Silva O. Teste ergométrico em crianças e adolescentes - comparação entre os protocolos de Bruce e Rampa. [dissertação]. Recife: Universidade Federal de Pernambuco; 2003.
• 15. IV Diretrizes Brasileiras de hipertensão arterial. Arq Bras Cardiol. 2004; 82 (supl 4): 1-14.
• 16. National High Blood Pressure education Program. The Fourth Report on the Diagnosis, Evaluation and Treatment of High Blood Pressure in Children and Adolescents. Pediatrics. 2004; 114: 555-76.
• 17. Williams CL, Hayman LL, Daniels SR, Robinson TN, Steinberger J, Paridon S, et al. Cardiovascular health in childhood. From the Committee on Atherosclerosis, Hypertension and Obesity in the Young (AHOY) of the Council on Cardiovascular Disease in the Young, American Heart Association. Circulation. 2002; 106: 143-60.
• 18. Pan American Hypertension Initiative. Working meeting on blood pressure measurement: suggestions for measuring blood pressure to use in populations surveys. Rev Panam Salud Publica. 2003; 14 (5): 300-2.
• 19. Lenk MK, Alehan D, Çeliker A, Alpay F, Sarici Ü. Bruce treadmill test in health turkish children: endurance time, heart rate, blood pressure and electrocardiographic changes. Turk J Pediatr. 1998; 40: 167-75.
• 20. Riopel DA, Taylor AB, Hohn AR. Blood pressure, heart rate, pressure-rate product and electrocardiographic changes in health children during treadmill exercise. Am J Cardiol. 1979; 44: 697-704.
• 21. Myers J, Buchanan BSN, Walsh D, Kraemer M, McAuley P, Hamilton-Wessler M, et al. Comparison of the ramp versus standard exercise protocols. J Am Coll Cardiol. 1991; 17: 1334-42.
• 22. Ahmad F, Kavey RE, Kveselis DA, Gaum WE, Smith FC. Response of non-obese children to treadmill exercise. J Pediatr. 2001; 139(2): 284-90.
• 23. Arenas Léon JL, Zajarias A, Fernández de la Vega P, Medrano G, Buendia A, Attié F. Response of normal children to the treadmill exercise test using the Bruce protocol. Arch Inst Cardiol Mex. 1985; 55 (3): 227-33.
• 24. Rodriguez de Roa E. Prueba de esfuerzo en adolescentes. Invest Clin. 1997; 38 (Suppl II): 47-54.

Publication Dates

• Publication in this collection
  21 May 2007
• Date of issue
  Mar 2007

History

• Accepted
  09 Oct 2006
• Reviewed
  31 Aug 2006
• Received
  02 May 2006